What is the geographical distribution of CO2 emissions? This column identifies the Earth’s “polluting centre of gravity” since 1970. It is heading east faster than GDP, which suggests that Asian production is getting more carbon-intensive.

In the run-up to a post-Kyoto agreement on greenhouse gas emissions, a major concern is the inclusion of the most important sources of global CO2 emissions. As these sources are linked to economic activity, it is largely suspected that their distribution across the Earth’s surface has shifted over recent decades. But in the absence of an indicator that takes the geographical dimension into account, it is difficult to come up with orders of magnitude regarding the direction and the speed of this process.

Quah (2009) uses the notion of a global centre of gravity to track shifts in the spatial distribution of global economic activity. Relying on the physical concept of centre of mass (or gravity) applied to GDP leads to the calculation of the world’s economic centre of gravity, which can be easily projected on the Earth’s surface and spotted over time. As it turned out, the world’s economic centre of gravity was located close to Iceland in the 70s, but has been steadily shifting towards Asia since then; it is now over Russia.

The same line of thinking can be used to track the centre of any global activity, including pollution. Relying on a new database on CO2 emissions (European Commission 2009), we provide estimates of the world’s polluting centre of gravity, which is obtained by using anthropogenic CO2 emissions as weights in the centre of mass calculations (Grether and Mathys, 2009a, b). Like GDP, the projection of the polluting centre of gravity on the Earth’s surface has shifted towards the East in recent decades.

CO2 emissions are shifting eastwards…

Figure 1 shows projections of the world’s polluting centre of gravity from 1970 to2005. Starting off the coast of Norway, its movement towards Asia is regular and accelerating (420 km in the 70s, 530km in the 80s, 460km in the 90s and 1000km from 2000 to 2005). These emissions exclude organic carbon and arise from a variety of different sources like fuel combustion, manufacturing activity, and residential heating. Each emission source can be used to construct an alternative centre of gravity with a trajectory similar to the one obtained for total emissions. Figure 1 shows industrial processes (which includes minerals, chemicals, pulp and paper and food) in addition to total emissions, because its eastern shift, apart from a brief slowdown beginning of the 80s, is particularly pronounced over the sample period (more than 2000km from 1990 to 2005).

Figure 1. Projection of the world’s polluting centre of gravity on the Earth’s surface

…more quickly than production

Since emissions are linked to economic activity, it is natural to compare the polluting centre of gravity with the world’s economic centre of gravity. GDP data for this alternative benchmark have been recently made available by Nordhaus and Chen (2009) at the level of a grid all over the globe, but only for three years during the 1990s. This allows drawing two basic conclusions.

First, on average, both projections are located on similar latitude, but the polluting centre is more than 20 degrees further east than the world’s economic centre of gravity. This suggests that Asia has higher pollution content than America and Europe in terms of average CO2 emissions per PPP dollar.

Second, over the 1990s, the polluting centre of gravity moved 1200km to the East while its economic counterpart remained along the Greenwich Meridian.

Although one should remain careful as the number of years is limited, this suggests that the pollution-intensity differential between Asia and America is getting more severe over time.

Figure 2. Comparison between the world’s polluting and economic centres of gravity